We wish to understand the manner in which behavioral responses aid in the maintenance of homeostasis. Our current focus is on the role of catecholamine-containing cells in mediating such behavior. We will study the effect of acute and chronic stress, such as exposure to cold, on such variables as norepinephrine and dopamine synthesis, tyrosine hydroxylase activity and cAMP. We will attempt to examine the value of these neurochemical responses in the promotion of appropriate thermoregulatory behavior by examining feeding, nest building and the extent to which subsequent severe stressors produce neurological deficits and/or appropriate behavioral responses.